Network devices include modules, cards, plugs, blades, and the like, which are used to implement some functionality in a network. As described herein, a network device is also a network element, namely a node or device performing some functionality in a network. Examples of network devices include, without limitation, switches, routers, firewalls, appliances, servers, optical terminals, and the like. Two examples of functional devices in a network element include a cooling module, which provides cooling, such as via fans and associated air flow, and a control module, which generally provides operations, administration, maintenance, and provisioning (OAM&P) functionality for the network device. The design trend is towards smaller form-factors, such as so-called “pizza boxes” (which are 1-2 rack unit (RU) high integrated shelves which may include various modules).
In some implementations, cooling modules have been combined with other types of functionality, such as control modules or access panels. Typically, a control module is located on a front side of a network device and plugs into a backplane or midplane. If space permits, control modules can be placed on a rear side of a network device next to cooling modules.
In some known systems, cooling modules have been combined with other modules. In some such known systems, if a single fan rotor malfunctions in a system in which cooling modules are combined with other modules, then the entire hybrid module needs to be replaced at a potentially great expense, with potential down time.
In some other known systems, the control module is located on the front side of a network device and plugs into the front of a mid-plane. In some such known systems, as shelves get shorter in height, the control modules can start to take up an increasingly greater size of the interface cards, thereby potentially resulting in smaller interface cards with possibly less functionality.
In some other known systems, the control module is located on the rear side of a network device next to cooling modules. In some such known systems, cooling capacity and cooling efficiency of the shelf may be reduced. Also, if cards of the control modules are located next to the cooling modules, then the cards of the control modules may not be able to be cooled by the cooling modules.